Sitting is more dangerous than smoking, kills more people than HIV and is more treacherous than parachuting. We are sitting ourselves to death."

You've probably heard the 'sitting is the new smoking' line before. But while Dr James Levine, director of the Mayo Clinic in the US, might be a bit extreme in his language in the above quote, the line has become a cliche for a reason: there is a mass of scientific evidence that shows that a sedentary lifestyle - sitting at a desk all day, getting in the car or train to commute home, then slumping in front of the telly - is terrible for your health.

Sitting for long periods slows down your metabolism, which is bad news for your cardiovascular health. Doctors have linked too much sitting to heart disease, various types of cancer, obesity, high cholesterol, type 2 diabetes - basically, sitting too much can shorten your life by years.

As a middle-aged man with a desk job, I have spent decades on my backside. And having successfully given up cigarettes some years back, I was startled to learn from Dr Levine that it might have been healthier to stay on the fags and give up work.

So, I decided to do something about it.

My first plan was exercise - I'd make sure I got out for a walk or a cycle or a swim most days. And this was in keeping with the best advice - the British Heart Foundation recommends a minimum 150 minutes per week of physical activity, maybe 30 minutes five times a week.

But then I learned that the negative effects on the heart from too much sitting are not reversed by exercise.

"Unfortunately, the research says that even if you are meeting those recommended guidelines, the time spent sitting isn't actually combated by the activity," says the Irish Heart Foundation's workplace health promotion officer, Enda Campbell.

This is because too much sitting increases coronary artery calcification, which leads to narrowing of the arteries and ultimately heart disease.

And studies, most notably one by the American College of Cardiology in 2015 in which 2,000 people wore motion-tracking devices, show there is no link between arterial calcification and the amount of exercise a person gets.

"It is a separate health risk," said Mr Campbell. "Generally, if you are sitting eight to 10 hours, and doing your 30 minutes a day, it doesn't actually combat the risk."

I was certainly sitting up to 10 hours a day, some days more. And I'm by no means an extreme case. A 2016 survey found that the average sitting time for the general population here was roughly six-and-a-half hours - but this was a 'self-report' survey and people generally under-estimate quite a lot.

"It would be fairly under-reported in my experience," says Mr Campbell. "Most people, if they are in a desk-based job, they'll be sitting for at least seven hours, then commuting each way, then most people would watch maybe two hours a day of TV, or their leisure time would be spent sitting as well.

"So, in my opinion, the average sitting time would be a lot higher than that. You're looking at potentially 10 hours of sitting time."

Working fewer hours was not an option, so I had only one solution - to work some of my hours standing up. I started to investigate getting a standing desk.

"The more sitting, the worse it is for your health; and the converse is true, the less sitting, the better," says Mr Campbell. "There is a saturation point where if you're standing for 12 to 14 hours a day, it does start to harm you in terms of posture or fatigue issues. But standing desks have been shown to reduce sitting time and they are effective - but often it isn't feasible to have those."

Which leads to my next problem: the cost and practicalities of a standing desk. In my small home office where I work, I don't have room for two desks I could move between - so I'd need a desk that was adjustable, or a sit/stand desk. A quick Google disabused me of this notion - full-on adjustable desks, many with motorised systems, are expensive and you can pay thousands.

There are websites and YouTube videos that show you how to build your own low-cost adjustable desk, but carpentry has never been my strong point.

The next best solution was a sit/stand attachment that sits on top of your normal desk. Another quick Google showed that these are generally pricey too, £400 to £500, and most of them are bulky, awkward, unsightly and - if you believe the reviews - seem to come with a raft of ergonomic and stability problems of their own. The cheaper ones tend to be too lightweight and take too long to adjust.

One crucial aspect for me was that it wouldn't be a lengthy production amid a tangle of cables to move from sitting to standing, or vice versa. And the ergonomics must be right - it had to be high enough and promote good posture.

I eventually went for something very simple called a Freedesk, I bought it online and it's discreet when it's not in standing position. It's also one of the cheapest options on the market at around £250. It's entirely wooden, good quality, and works with a bungee cord system to give it its springiness to help you lift it into standing position.

The first day was weird - being on my feet was quite distracting. I found myself stepping away from the computer to look out the window if I heard any noise on the street, something I'd never do if I was seated. But after a few days, standing at the desk became normal.

I found there are different types of work that lend themselves more to either sitting or standing - if I've got a long read, or emails to answer, I'll do that standing up; if I've got to do a lot of typing, or I'm very busy approaching a deadline, sitting seems better.

I don't have a set regime, I do what I feel comfortable with. If I get stiff or tired either sitting or standing, I can change within about 10 seconds.

I'm about three months in to my new sit/stand lifestyle, and so far, so good. I've actually lost a few kilos and I'm hopeful that my next blood test will reveal I no longer have the cholesterol levels of an elderly sloth.

Since 2014, employers in Denmark are legally obliged to offer workers the option of a standing desk. So how long before other governments will see the preventative benefits of sit/stand desks in relieving pressure on overburdened health services?

And surely employers can see the benefits to productivity from having a healthier workforce?

Mr Campbell stresses that while standing desks can be a good solution, you certainly don't need one to be healthy. You just need to stand up and move more often.

"Breaking up the sitting time is the most important thing," he says, "maybe even 30 seconds of standing up. Most office workers come in at 9am and mightn't stand until lunchtime, at 12 or 1 o'clock.

"So, if you stand up for maybe a minute here or there, maybe to go to the bin or go to the printer… even going to have a chat with a colleague instead of emailing them from 10 yards away, those are the small things that can make a big difference."